The present invention deals with power machines. More specifically, the present invention deals with electronic controls of hydraulic cylinders on a skid steer loader.
Power machines, such as skid steer loaders, typically have a frame which supports a cab or operator compartment and a movable lift arm which, in turn, supports a work tool such as a bucket. The movable lift arm is pivotally coupled to the frame of the skid steer loader and is powered by power actuators which are commonly hydraulic cylinders. In addition, the tool is coupled to the lift arm and is powered by one or more additional power actuators which are also commonly hydraulic cylinders. An operator manipulating a skid steer loader raises and lowers the lift arm and manipulates the tool, by actuating the hydraulic cylinders coupled to the lift arm, and the hydraulic cylinder coupled to the tool. Manipulation of the lift arm and tool is typically accomplished through manual operation of foot pedals or hand controls which are attached by mechanical linkages to valves (or valve spools) which control operation of the hydraulic cylinders.
Skid steer loaders also commonly have an engine which drives a hydraulic pump. The hydraulic pump powers hydraulic traction motors which provide powered movement of the skid steer loader. The traction motors are commonly coupled to the wheels through a drive mechanism such as a chain drive. A pair of steering levers are typically provided in the operator compartment which are movable fore and aft to control the traction motors driving the sets of wheels on either side of the skid steer loader. By manipulating the steering levers, the operator can steer the skid steer loader and control the loader in forward and backward directions of travel.
It is also common for the steering levers in the operator compartment of the skid steer loader to have hand grips which support a plurality of buttons or actuable switches. The switches are actuable by the operator and are configured to perform certain functions.